As cities grapple with escalating climate, resource, and demographic challenges, the convergence of smart technologies and circular economy (CE) principles is emerging as a transformative pathway toward sustainable urban development. This chapter explores how digital innovations specifically Artificial Intelligence (AI), Digital Twins, and Internet of Things (IoT) can be synergistically combined with regenerative urban planning and ESG-aligned finance to advance the vision of circular smart cities. Drawing from interdisciplinary theoretical frameworks spanning transition theory, participatory governance, and socio-technical systems, the chapter proposes a holistic model that centers not only on technological optimization but also on inclusive governance and institutional capacity building. Empirical insights from global investment trends reveal that leading urban centers like Singapore, Amsterdam, and London are at the forefront of integrating CE into smart infrastructure through targeted projects and green finance. Simultaneously, secondary data from the UN, World Bank, and local government reports underscores the role of digital data ecosystems in enhancing urban intelligence and circularity metrics. By mapping patterns in CE project proliferation and smart investments, the chapter demonstrates a positive correlation between AI-enabled decision systems and improved sustainability outcomes. A comparative case study analysis of India, Brazil, and Indonesia further contextualizes the global discourse, highlighting localized adaptations of digital twin technologies, waste valorization, and ESG-compliant procurement systems. While cities such as Pune, Curitiba, and Jakarta showcase innovation, institutional asymmetries and financing gaps remain significant barriers to scalability and systemic transition. The policy analysis section identifies regulatory fragmentation, lack of data interoperability, and limited digital ethics frameworks as key inhibitors. It argues for the creation of boundary-spanning governance models and anticipatory regulatory frameworks that align CE objectives with dynamic smart-city infrastructures. The final roadmap provides a time-bound strategy to guide urban actors from pilot experimentation to integrated, systemic transformation by 2030. In conclusion, this chapter positions circular smart cities not merely as a technological ambition but as a socio-political imperative. The integration of AI and CE within urban governance must be driven by equity, transparency, and collective intelligence. Only by institutionalizing ethical foresight, ESG literacy, and community co-creation can cities ensure a regenerative and inclusive urban future.